================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common+0x100/0x21a0 kernel/locking/mutex.c:587 Read of size 8 at addr ffff0000d63d8130 by task jffs2_gcd_mtd0/6169 CPU: 1 PID: 6169 Comm: jffs2_gcd_mtd0 Not tainted 6.8.0-rc7-syzkaller-g707081b61156 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x178/0x518 mm/kasan/report.c:488 kasan_report+0xd8/0x138 mm/kasan/report.c:601 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 __mutex_lock_common+0x100/0x21a0 kernel/locking/mutex.c:587 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_interruptible_nested+0x2c/0x38 kernel/locking/mutex.c:826 jffs2_garbage_collect_pass+0xa4/0x1a50 fs/jffs2/gc.c:134 jffs2_garbage_collect_thread+0x414/0x48c fs/jffs2/background.c:155 kthread+0x288/0x310 kernel/kthread.c:388 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 Allocated by task 6163: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:575 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x26c/0x49c mm/slub.c:4012 kmalloc include/linux/slab.h:590 [inline] kzalloc include/linux/slab.h:711 [inline] jffs2_init_fs_context+0x58/0xc8 fs/jffs2/super.c:313 alloc_fs_context+0x514/0x7a4 fs/fs_context.c:318 fs_context_for_mount+0x34/0x44 fs/fs_context.c:332 do_new_mount+0x14c/0x900 fs/namespace.c:3331 path_mount+0x590/0xe04 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3875 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Freed by task 6163: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:589 poison_slab_object+0x124/0x18c mm/kasan/common.c:240 __kasan_slab_free+0x3c/0x70 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2121 [inline] slab_free mm/slub.c:4299 [inline] kfree+0x144/0x3cc mm/slub.c:4409 jffs2_kill_sb+0x9c/0xb0 fs/jffs2/super.c:350 deactivate_locked_super+0xc4/0x12c fs/super.c:472 deactivate_super+0xe0/0x100 fs/super.c:505 cleanup_mnt+0x34c/0x3dc fs/namespace.c:1267 __cleanup_mnt+0x20/0x30 fs/namespace.c:1274 task_work_run+0x230/0x2e0 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x618/0x1f64 kernel/exit.c:871 do_group_exit+0x194/0x22c kernel/exit.c:1020 __do_sys_exit_group kernel/exit.c:1031 [inline] __se_sys_exit_group kernel/exit.c:1029 [inline] pid_child_should_wake+0x0/0x1dc kernel/exit.c:1029 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 The buggy address belongs to the object at ffff0000d63d8000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 304 bytes inside of freed 4096-byte region [ffff0000d63d8000, ffff0000d63d9000) The buggy address belongs to the physical page: page:0000000090c7b243 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1163d8 head:0000000090c7b243 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x5ffc00000000840(slab|head|node=0|zone=2|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 05ffc00000000840 ffff0000c0002140 fffffdffc35b8600 dead000000000002 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d63d8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d63d8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000d63d8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d63d8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d63d8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Unable to handle kernel paging request at virtual address dfff800009a6e488 KASAN: probably user-memory-access in range [0x000000004d372440-0x000000004d372447] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff800009a6e488] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 6169 Comm: jffs2_gcd_mtd0 Tainted: G B 6.8.0-rc7-syzkaller-g707081b61156 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : mtd_get_master include/linux/mtd/mtd.h:405 [inline] pc : mtd_erase+0x98/0x5cc drivers/mtd/mtdcore.c:1372 lr : mtd_get_master include/linux/mtd/mtd.h:405 [inline] lr : mtd_erase+0xb4/0x5cc drivers/mtd/mtdcore.c:1372 sp : ffff800097867740 x29: ffff800097867840 x28: dfff800000000000 x27: ffff700012f0cef8 x26: ffff8000978677e0 x25: dfff800000000000 x24: ffff0000ce86a640 x23: ffff0000c9a24b00 x22: 1fffe0001adc3910 x21: 000000004d372444 x20: 000000004d371dfc x19: 000000004d371dfc x18: 1fffe000367fff96 x17: ffff800080255c0c x16: ffff800080276f8c x15: 0000000000000001 x14: 1ffff00011ea7bfa x13: 0000000000000000 x12: ffff800084f9ea54 x11: ffff80008e48b7f0 x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 0000000009a6e488 x7 : ffff8000809fd024 x6 : ffff8000809f9f7c x5 : ffff0000d5968458 x4 : ffff8000978675e8 x3 : ffff80008184d698 x2 : 0000000000000000 x1 : ffff0000ce86a640 x0 : ffff0000c9a24b00 Call trace: mtd_get_master include/linux/mtd/mtd.h:405 [inline] mtd_erase+0x98/0x5cc drivers/mtd/mtdcore.c:1372 jffs2_erase_block fs/jffs2/erase.c:63 [inline] jffs2_erase_pending_blocks+0xa94/0x1fcc fs/jffs2/erase.c:140 jffs2_garbage_collect_pass+0x554/0x1a50 fs/jffs2/gc.c:253 jffs2_garbage_collect_thread+0x414/0x48c fs/jffs2/background.c:155 kthread+0x288/0x310 kernel/kthread.c:388 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 Code: 96d62acf aa1703f3 91192275 d343fea8 (387c6908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 96d62acf bl 0xfffffffffb58ab3c 4: aa1703f3 mov x19, x23 8: 91192275 add x21, x19, #0x648 c: d343fea8 lsr x8, x21, #3 * 10: 387c6908 ldrb w8, [x8, x28] <-- trapping instruction